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linux:administration:kernel

Kernel

Info

  • query CPU information: cpuid
  • show system/kernel info: uname -a
  • show kernel (boot) messages: dmesg
  • show (or configure) kernel parameters at runtime: sysctl -a
  • show kernel memory usage: free
  • show modules loaded: lsmod
  • show all module parameters: modinfo -p <modname>
  • show current module parameters: systool -m <modname> -av
  • configure to show more kernel messages (with timestamp)
    echo 8 > /proc/sys/kernel/printk
    echo Y > /sys/module/printk/parameters/time

PCI

  • show PCI information: lspci -k -nn

USB

  • show tree of USB devices: lsusb -t

Bluetooth

Troubleshooting

Checklist:

  1. check kernel module btusb is load and running: lsmod | grep btusb
  2. check for kernel problems: dmesg | grep -i bluetooth
  3. check Bluetooth status: sudo systemctl status bluetooth, or sudo service bluetooth status
  4. after changing files in /etc/bluetooth do: sudo service bluetooth restart
  5. use sudo bluetoothctl to check for Bluetooth devices and their state (also the Blueman applet might be useful for this)
  6. check Laptop Power Management for Bluetooth status: sudo tlp-stat -u -v
  7. change /etc/default/tlp to adjust Laptop Power Management regarding Bluetooth:

Udev

Links

Commands

  • show udev daemon1) events: udevadm monitor --environment
  • after changing udev rules: udevadm control --reload

Files

  • /etc/udev/rules.d, /lib/udev/rules.d: udev rules

Storage Devices

  • show all block devices: lsblk
  • show hard drive information: hdparm -I /dev/sda
  • blacklist the UAS driver for LaCie USB mass storage in file /etc/modprobe.d/usb-storage-quirks.conf:2)
    # Do not use USB driver UAS (USB Attached SCSI) with LaCie mass storage.
    # This is a younger USB 3.x protocol and not stable at the moment.
    # See usb-storage.quirks in https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt
    options usb-storage quirks=059f:105e:u
1)
User space device manager for /dev.
linux/administration/kernel.txt · Last modified: 2021/10/31 11:49 by Ralf Hoppe